1. Field of the Invention
This invention relates to unsaturated silylated vinyl alcohol polymers, that is, polymers of conjugated polyenyloxysilanes and copolymers thereof with ethenyloxysilanes, and to their preparation.
2. Background
(1,3-Butadienyloxy)trialkylsilanes are known compounds or are prepared by known methods. For example, U.S. Pat. No. 3,472,888 discloses the preparation of (1,3-butadienyloxy)trihydrocarbylsilanes. Brun et al., Tetrahedron Lett., 24(4): 385 (1983) disclose (1,3-butadienyloxy)trimethylsilane and 1,3-butadienenyacetate. Makin et al., Kh. Org. Khim., 18(2): 287 (1982) disclose the preparation of (1,3-butadienyloxy)trimethylsilanes by silylating .alpha.,.beta.-unsaturated aldehydes with trimethylsilyl chloride and triethylamine. Jung et al., Tetrahedron Lett., 3791 (1977) disclose the preparation of ethenyloxysilanes from lithium enolates of aldehydes by reaction with trialkylsilyl chlorides.
Polymers prepared from (1,3-butadienyloxy)trialkylsilanes are also known. Mukaiyama et al., Chem. Lett., 4: 319 (1975) disclose the formation of polymer in the titanium tetrachloride-catalyzed reaction of (1,3-butadienyloxy)trimethylsilane when methylene chloride or toluene were used as solvents. Polymer was not formed when a more strongly complexing solvent (THF) was employed or when titanium isopropoxide was added to the titanium tetrachloride. Makin et al., Zh. Org. Khim., 19(11): 2285 (1983) disclose reaction of 1,3-butadienyloxytrimethylsilanes with acetals catalyzed by zinc chloride without polymerization. Makarov et al., Vysokomol. Soedin. Ser. B, 13(3): 222 (1971) disclose copolymerization of 1- and 2-acetoxy-1,3-butadiene with styrene and methyl methacrylate. USSR patent application No. 285,238-S discloses copolymerization of 1,3-butadienyltrialkylsilanes with various vinyl monomers including styrene and methyl methacrylate using free radical catalysts.
U.S. Pat. No. 3,491,068 discloses 1:1 alternating copolymers of maleic anhydride and diolefins, including 1- and 2-alkoxy-1,3-butadienes prepared by free radical polymerization. U.S. Pat. No. 3,458,491 discloses anionic (co)polymerization of various dienes, including 1- and 2-alkoxy-1,3-butadienes. The catalyst was an alkali metal alkyl or aryl or complexed alkali metal. U.S. Pat. No. 1,963,108 discloses the preparation of 1- and 2-acyloxy-1,3-butadienes and their free-radical polymerization. U.S. Pat. No. 3,993,847 discloses adhesives comprising copolymers of conjugated dienes including 1- and 2-alkoxy-1,3-butadienes. U.S. Pat. No. 3,418,293 discloses polymerization of vinyloxysilanes of the formula CH.sub.2 .dbd.CHOSi(R.sup.1)(R.sup.2)(R.sup.3) wherein R.sup.1-3 are the same or different, and each is a hydrocarbon radical which can include alkyl, cycloalkyl, aryl, aralkyl, and alkaryl, in the presence of an ionic catalyst of the Friedel-Crafts or Ziegler type, at a temperature in the range -80.degree. C. to 0.degree. C., in an anhydrous organic solvent. The product was a poly[(ethenyloxy)triorganosilane] which can be converted to poly(vinyl alcohol) by alcoholysis.
Murahashi et al., Polymer Letters, 3: 245 (1965) and 4: 59, 65 and 187 (1966), disclose the preparation of poly(vinyltrimethylsilyl ethers) by radical and cation-initiated polymerization of vinyloxy trimethylsilane and conversion thereof to stereoregular poly(vinyl alcohol). Also disclosed is the radical-initiated copolymerization of vinyloxy trimethylsilane ([ethenyloxy]trimethylsilane) with vinyl comonomers. Cationic initiators employed were SnCl.sub.4 or ethyl aluminum chlorides. Nozakura et al., J. Polymer Sci., Polymer Chem. Ed., 11: 1053 (1973), disclose the polymerization of several ethenyloxy trialkylsilanes initiated by cationic compounds SnCl.sub.4 or ethyl aluminum chlorides, and conversion of the poly(vinyltrialkylsilyl ethers) to poly(vinyl alcohol) with aqueous hydrofluoric acid. Runge et al., Makromol. Chem., 120: 148 (1968), disclose the free radical-initiated copolymerization of ethenyloxytrimethylsilane with vinyl comonomers. Japanese published, unexamined application No. JA 22299/69 discloses a process of copolymerizing ethenyloxytrialkylsilanes with vinyl comonomers in the presence of radical catalysts such as azo-bis(isobutyronitrile). Colvin, "Silicon in Organic Synthesis", Butterworths, 1981, pages 219-220, discloses the reaction of alicyclic silyl enol ethers with aldehydes in the presence of a fluoride ion catalyst, for example, ##STR1## Colvin, ibid, page 227, discloses the reaction of aromatic aldehydes with silyl ketene acetals in the presence of TiCl.sub.4 ; the silyl group in the product is subsequently removed by hydrolysis, for example, ##STR2## Colvin, ibid, pages 221 and 222, discloses the alkylation of silyl enol ethers with certain alkyl and aralkyl halides in the presence of TiCl.sub.4 or ZnBr.sub.2, for example, ##STR3## Colvin, ibid, pages 232-236, discloses the reaction of silyl enol ethers with acyl halides, halogenated acid anhydrides and ketones in the presence of Lewis acids.
U.S. Pat. No. 4,544,724 discloses the polymerization of ethenyloxysilanes initiated by aldehydes or precursors thereof, and catalyzed by selected Lewis acids, including zinc halides. The polymers are aldehyde-terminated poly(ethenyloxysilanes), hydrolyzable to poly(vinyl alcohol), and copolymers thereof.
The conversion of pendant siloxy groups, such as --OSi(CH.sub.3).sub.3, to hydroxyl groups in polymers by a variety of methods is disclosed in the aforesaid publications of Murahashi and Colvin and in the Japanese publication.
U.S. Pat. No. 2,165,962 and Hoaglin et al., J. Am. Chem. Soc., 71: 3468 (1949) describe the polymerization of alkyl vinyl ethers in the presence of acetals such as acetaldehyde acetal and a Lewis acid such as BF.sub.3 to form acetal-capped polyvinyl ethers; for example, ##STR4## Acetal-initiated polymerization of trialkylsilylvinyl ethers is not disclosed. Formation of unsaturated aldehydes by hydrolysis of a 1,1,3 trialkoxy product formed by the condensation of an acetal with a vinyl ether is disclosed by Fishman et al., Synthesis Comm., 137 (1981); for example, ##STR5##